2.3. Synthesis of APTES modified SPIONs
A suspension of SPIONs was prepared with a concentration of 0.5 M in ethanol and sonicated for 30. Then, a 10 ml APTES solution, 10% v/v, was added to the solution and stirred for five h. The final product was purified five times with ethanol by magnetic separation. Then, the obtained APTES modified SPIONs were dried at room temperature to remove excess solvent.